Reutilization of mango byproducts: study of the effect of extraction solvent and temperature on their antioxidant properties.
Mango biowastes, obtained after processing, contain large amounts of compounds with antioxidant activity that can be reused to reduce their environmental impact. The present study evaluates the effect of solvent (methanol, ethanol, acetone, water, methanol:water [1:1], ethanol:water [1:1], and acetone:water [1:1]), and temperature (25, 50, and 75 °C) on the efficiency of the extraction of antioxidants from mango peel and seed. Among the factors optimized, extraction solvent was the most important. The solvents that best obtained extracts with high antioxidant capacity were methanol, methanol:water, ethanol:water, and acetone:water (β-carotene test, antioxidant activity coefficient 173 to 926; thiobarbituric acid reactive substances test, inhibition ratio 15% to 89%; 2,2'-azino-bis-(3-ethylbenzothiazoline)-6-sulfonic acid ABTS(·+); and 2,2-diphenyl-1-picrylhydrazyl DPPH· scavenging, 7 to 22 and 8 to 28 g trolox equivalent antioxidant capacity [TE] per 100 g mango biowaste on a dry matter basis [DW]). Similarly, the flavonoid (0.21 to 1.4 g (+)-catechin equivalents per 100 g DW), tannin (3.8 to 14 g tannic acid equivalents per 100 g DW), and proanthocyanidin (0.23 to 7.8 g leucoanthocyanidin equivalents per 100 g DW) content was highest in the peel extracts obtained with methanol, ethanol:water, or acetone:water and in the seed extracts obtained with methanol or acetone:water. From the perspective of food security, it is advisable to choose ethanol (which also has a notable antioxidant content), ethanol:water, or acetone:water, as they are all solvents that can be used in compliance with good manufacturing practice. In general, increasing temperature improves the capacity of the extracts obtained from mango peel and seed to inhibit lipid peroxidation; however, its effect on the extraction of phytochemical compounds or on the capacity of the extracts to scavenge free radicals was negligible in comparison to that of the solvent.
There are many antioxidant compounds in mango peel and seed, and they could be used as a natural and very inexpensive alternative to synthetic food additives. However, the conditions in which the antioxidants are extracted must be optimized. This work proves that conditions such as extraction solvent or temperature have a crucial impact on obtaining extracts rich in antioxidants from mango biowastes.
Dorta E
，Lobo MG
，Gonzalez M
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Volatile aroma components and antioxidant activities of the flavedo peel extract of unripe Shiikuwasha (Citrus depressa Hayata).
The flavedo peel extracts of unripe Shiikuwasha (Citrus depressa Hayata) fruits were extracted using steam distillation (SD) or a cold-press (CP) system. Volatile aroma content and composition were determined using gas chromatography (GC) and each compound was identified using gas chromatography-mass spectrophotometry (GC-MS). The major constituents of the extracts were monoterpene hydrocarbons (91.75-93.75%[709.32-809.05 mg/100 g of fresh flavedo peel]) including limonene (43.08-45.13%[341.46-379.81 mg/100 g of fresh flavedo peel]), γ-terpinene (27.88-29.06%[219.90-245.86 mg/100 g of fresh flavedo peel]), and p-cymene (8.13-11.02%[61.47-97.22 mg/100 g of fresh flavedo peel]). The extraction process used was determined to be a decisive factor that affects the composition of key citrus aroma components, as well as the antioxidant activities of the Shiikuwasha fruit. Antioxidant capabilities of the extracts were examined by assay of 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging activity and β-carotene bleaching inhibition. The cold-press extraction system may better retain the total phenolic content of the flavedo peel and display superior antioxidant activities, compared to the steam distillation extraction method.
Shiikuwasha (Citrus depressa Hayata) is a type of small citrus fruit, and has been used as raw material for beverage and food additive productions in Japan. It had a unique aroma composition in which the limonene content of its peels is lower than that of other commonly known citrus peels. The present study detailed the volatile aroma composition, as well as antioxidant capabilities of Shiikuwasha peel extracts of different extraction methods, that are cold-press and steam distillation methods. The results of this study may provide a basis for selection of Shiikuwasha peel extracts in food industry for citrus flavor production.
Asikin Y
，Taira I
，Inafuku S
，Sumi H
，Sawamura M
，Takara K
，Wada K
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ResearchGate
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钛学术
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